University of Missouri food scientists have developed a faster, more accurate lab test for use in detecting the live salmonella bacterium.

The new test, developed by Associate Professor of Food Science Azlin Mustapha and MU graduate student Luxin Wang, modifies the existing polymerase chain reaction technique to include a dye that is used on food samples before they're tested. The dye cannot penetrate live cells but can enter dead cells, making the dead cells insoluble and invisible to PCR tests. “DNA-based methods are available right now that can get the company results in a shorter amount of time, but these methods do not differentiate between the live and the dead salmonella,” said Mustapha. “Live salmonella are the ones that can kill consumers, not the dead ones, but false positives can result in a large number of unnecessary food recalls.”

The modified technique provides results in 12 hours, versus the five days required for the traditional method. “The technique can allow the poultry industry accurately and rapidly test for contamination before the product is shipped," said Mustapha. "For elderly and immunocompromised individuals, this is very important because they are sensitive and more susceptible.”